The present invention relates to an intraocular lens injector, and more particularly to an injector head forming a hollow cone of spreadable leaves for partial insertion into a minimum size eye incision to inject a temporarily folded, i.e. deformable, intraocular lens into the eye, and to an assembly of the cone and an injector device having a holder with a bore to hold the folded lens and connected to the cone, and a plunger to push the lens from the bore and through the cone for controlled gradual injection into, and simultaneous controlled gradual unfolding within, the eye, and a method of so using the assembly.
In eye surgery for treating conditions such as natural eye lens cataracts, a common procedure is to remove the cataracted lens through an incision in the cornea of the eyeball, and replace it by an artificial intraocular lens. The intraocular lens, typically 6 mm in diameter, is usually temporarily resiliently deformable, i.e. foldable into generally cylindrical shape, by curling, etc., to reduce its girth, and while kept folded is inserted through a corneal incision, typically 3.5-4 mm long, to minimize patient trauma. The lens has a lens body or optic, e.g. of soft material such as silicone, with normally stiffer resiliently deformable position fixation means or haptics, e.g. of polypropylene, extending therefrom to seat the lens in the eye.
The haptics are kept in stable relation to the folded lens body during insertion into the eye so as to pass without difficulty through the incision. Once inserted, unfolding the lens body and haptics in the confined space at the implantation site must be controlled to avoid patient trauma from contact of these expanding mechanical elements with the inner wall of the cornea or other eye parts. Inserting the folded lens into an eye so as to minimize patient trauma is very difficult. A tool is needed to hold and insert the folded lens, requiring an incision large enough to accommodate both. Often, a separate retainer keeps the lens folded, so that the inserted retainer and tool clutter the eye interior during lens unfolding, after which the tool and retainer must be retrieved via the incision.
U.S. Pat. No. 4,573,998 to Mazzocco shows various tools to insert a deformable lens through an incision into the eye by pushing, stretching, ejecting or compressing technique. The lens and/or tool grossly contact the incision during insertion and the lens must be released carefully in the eye to keep the expanding lens elements from injuring internal eye parts.
U.S. Pat. No. 4,906,247 to Fritch shows a deformable lens held folded by forceps inserted in a stretchable plastic tube so as to stretch the tube diameter and also squeeze the tube around the folded lens like a mitten. Upon inserting the lens into the eye, the forceps must release it with great care to keep the expanding lens elements from injuring internal eye parts.
U.S. Pat. No. 4,911,714 to Poley shows a deformable lens held folded by sutures connecting apertures on opposed edges of the lens, or by integral lock means or adhesive on such edges, for insertion by a first tool through a first incision into the eye. A second tool inserted through a second incision is used to cut and remove the sutures, unlock the lock means or break the adhesive bond while the first tool holds the lens to keep the expanding lens elements from injuring internal eye parts.
U.S. Pat. No. 4,917,680 to Poley shows a deformable lens held folded by a severable retainer or band for insertion by a first tool through a first incision into the eye. A second tool inserted through a second incision is used to sever and remove the band while the first tool holds the lens to keep the expanding lens elements from injuring internal eye parts.
U.S. Pat. No. 4,976,716 to Cumming shows an insertion device with telescoping inner and outer tubes, and a plunger in the inner tube, for a deformable lens having leading and trailing haptics. Two opposed flexible, widely diverging, inner fingers integral with the inner tube front are notched near their free ends to form bendable tips. Two opposed rigid outer fingers pivoted to the outer tube front are lockable to hold the inner fingers in narrower diverging state when the inner tube is retracted in the outer tube so that only its tips protrude. Jaws on a lens loading tray squeeze and fold the lens between the inner fingers so that the leading haptic protrudes from their narrower diverging tips, and then the outer fingers are locked.
The leading haptic and diverging finger tips are inserted into the eye incision, and a lever and ratchet drive on the device is used to move the inner tube and plunger forwardly of the outer tube until the inner finger notches clear the incision, enabling the stored force of the folded lens to bend the inner finger tips outwardly of their widely diverging position for partial lens unfolding. Further use of the drive causes the plunger to push the lens beyond the inner finger tips for complete lens unfolding. A spring return of the drive is used to retract the plunger and inner tube from the incision. The device is complex, costly and cumbersome to operate, and its diverging fingers stress the incision or require use of a larger incision. As the fingers do not surround the folded lens, but only hold its diametrically opposed girth portions, the outwardly projecting girth portions therebetween can contact and stress the incision and inner wall of the cornea during the insertion procedure.
Also, a device manufactured by Allergen Inc., known as "The Prodigy," includes a lens injector having a straight, rigid tubular portion whose tip is inserted into the incision and through which the folded lens is injected into the eye. The tip is not tapered and has no means to control unfolding of the lens.
It would be desirable to insert a temporarily folded intraocular lens through a minimum size incision into the eye by an instrument that does not unduly stress or traumatize the incision, permitting controlled gradual lens injection and unfolding in the confined space within the eye, while avoiding incision trauma from such stress or contact of the unfolding lens with the inner wall of the cornea or other eye parts.